VI CONTENTS OF VOL. XL. SIXTH SERIES. 



Page 

 Prof. Eric K. Eideal on the Velocity of Unimolecular lie- 

 actions , . .\ 461 



Mr. J. H. J. Poole on the Eadiurn Content of the Eocks of 



the Loetschberg Tunnel 466 



Dr. Megh Nad Sana on Ionization in the Solar Chromosphere. 472 

 Mr. Herbert Bell on the Helium-Hydrogen Series Constants. 489 

 Dr. S. E. Milner on the Internal Energy of the Lorentz 



Electron 494 



Prof. A. Anderson on the Orbit of a Planet 499 



Sir J. A. Ewing on the Specific Heat of Saturated Vapours 



and the Entropy-Temperature Diagrams of certain Fluids. 501 

 Mr. J. E. Clarke on the Thermal Conductivity of some Solid . 



Insulators 502 



Prof. J. S. Townsend on the Collisions of Electrons with 



Molecules of a Gas 505 



Mr. S. Eatner on the Pressure on the .Poles of an Electric 



Arc 511 



Mr. T. C. Tobin on a Method of Finding a Parabolic Equation 



of the rth Degree for any Graphically Paired Curve .... 513 



Prof. A. O. Eankine on the Dimensions of Atoms 516 



Prof. S. J. Barnett on a Double Solenoid for the Production 



of Uniform Magnetic Fields 519 



NUMBEE CCXXXIX.— NOVEMBEE. 



Dr. John Prescott on the Torsion of Closed and Open Tubes. 521 



Mr. Seibei Konno on the Variation of Thermal Conductivity 

 during the Fusion of Metals 512 



Prof. K. T. Compton : Ionization and Production of Eadiation 

 by Electron Impacts in Helium investigated by a New 

 Method ". 553 



Messrs. C. N. Hinshelwood and E. J. Bowen on the Eate of 

 Chemical Action in the Crystalline State 569 



Mr. Humphrey D. Murray on the Precipitation of Colloids . 578 



The Eeseareh Staff of the General Electric Company on the 

 Disappearance of Gas in the Electric Discharge. (Work 

 conducted by N. E. Campbell and J. W. II. Eyde) 585 



Prof. Barton and Miss Browning on Triple Pendulums 

 with Mutual Interaction and the Analogous Electrical 

 Circuits.— I. (Plates XI.-XIII.) 611 



Mr. Satyendra Nath Basu on the Deduction of Eydberg's Law 

 from the Quantum Theory of Spectral Emission 619 



Dr. F. W. Aston on the Mass-Spectra of Chemical Elements. 

 (Part 2.) (Plate XIV.) 628 



Prof. E. Whiddington on the Ultra-Micrometer : an appli- 

 cation of the Thermionic Valve to the measurement of 

 very small distances. (Plate XV.) 634 



